delete `nix eval --write-to` #974

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opened 2025-08-21 12:31:09 +00:00 by pennae · 4 comments

pennae commented

2025-08-21 12:31:09 +00:00

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❯ nix eval --write-to new-dir --expr '{ "../snafu" = "this should never ever work"; }' && cat snafu
this should never ever work

this is obviously nonsense. we don't even use --write-to in our tree any more because it was so busted, and it only existed in the first place to make the old makefile-based doc build system less impossible to not fuck up. we have found only three occurences of this flag on sourcegraph that aren't nix implementations:

an old version of cppnix packaging in void linux (current packaging doesn't use --write-to)
as context in slackware user packages
one specific packaging of helix that uses the flag to write a json file and should really just be shoving that json through stdout

given how busted and overall not useful this "feature" is we should really just axe it

cc @commentatorforall

``` ❯ nix eval --write-to new-dir --expr '{ "../snafu" = "this should never ever work"; }' && cat snafu this should never ever work ``` this is obviously nonsense. we don't even use `--write-to` in our tree any more because it was so busted, and it only existed in the first place to make the old makefile-based doc build system less impossible to not fuck up. we have found only three occurences of this flag on sourcegraph that aren't nix implementations: - an old version of cppnix packaging in void linux (current packaging doesn't use `--write-to`) - [as context in slackware user packages](https://github.com/SlackBuildsOrg/slackbuilds/blob/master/system/nix/config/fix_nix_options.patch) - [one specific packaging of helix](https://github.com/chaotic-cx/nyx/blob/main/pkgs/helix-git/default.nix) that uses the flag to write a json file and should really just be shoving that json through stdout given how busted and overall not useful this "feature" is we should really just axe it cc @commentatorforall

jade commented

2025-08-21 14:42:07 +00:00

Owner

#227

https://git.lix.systems/lix-project/lix/issues/227

pennae commented

2025-08-21 19:37:33 +00:00

Author

Owner

let's just fucking do it

jade commented

2025-08-21 19:56:13 +00:00

Owner

yeah, let's make it a specific error that says we removed it. other than that, I have no objections, let's send it directly into a release.

pennae self-assigned this

2025-08-21 20:41:27 +00:00

lix-bot commented

2025-08-22 12:31:21 +00:00

Member

This issue was mentioned on Gerrit on the following CLs:

commit message in cl/4045 ("nix/eval: remove --write-to")

This issue was mentioned on Gerrit on the following CLs: * commit message in [cl/4045](https://gerrit.lix.systems/c/lix/+/4045) ("nix/eval: remove --write-to")